<!DOCTYPE html>
<html lang="zh-CN">
    <head>
        <meta charset="UTF-8" />
        <title>19_CSS3-新增盒子属性-opacity</title>
        <style>
            #outer {
                width: 500px;
                height: 300px;
                background-image: url(./img/bg03.jpg);
                border: 2px solid black;
            }

            #inner {
                height: 100px;
                background-color: #000;
                margin-top: 80px;
                color: aliceblue;
                text-align: center;
                line-height: 100px;
                font-size: 50px;

                /* 不透明度  值越小 透明越高 */
                opacity: .5;
            }
        </style>
    </head>
    <body>
        <div id="outer">
            <div id="inner">
                天气很好，出去浪。
            </div>
        </div>
    </body>
</html>